1. Field of the Invention
The present invention relates to a medical image diagnosis assisting technology for outputting an image useful for image diagnosis of a cardiac region based on a three-dimensional medical image.
2. Description of the Related Art
Medical image analysis techniques have been advancing rapidly with a wide spread use of multi-detector row computed tomography in clinical practice. For example, in the field of cardiac medicine, it has become possible to obtain a plurality of three-dimensional images within one heartbeat. Along with this, various image diagnosis assisting methods using a three-dimensional medical image of cardiac region have been proposed.
In most cardiac diseases, the supply of blood flow to the myocardium is stopped and the myocardium becomes unable to work, thereby causing cardiac arrest. Therefore, it is necessary to discover a myocardial abnormality by image diagnosis and determine the treatment policy as soon as possible. The angina pectoris and myocardial infarction are the typical examples of cardiac disease caused by ischemia in which the blood flow to the myocardium is reduced. The difference between the angina pectoris and myocardial infarction lies whether or not the myocardium can be recovered in the days ahead. Whereas in the case of angina pectoris, the myocardium can be recovered, it cannot be recovered in the case of myocardial infarction because the myocardium has already been necrotized. In the case of angina pectoris, revascularization therapies, such as the surgery for expanding the constricted portion of the coronary artery causing insufficient blood flow to the myocardium (percutaneous coronary intervention (PCI)) or coronary artery bypassing surgery, may be implemented as the treatment method. Consequently, it is extremely important to diagnose whether the patient has angina pectoris or myocardial infarction.
As image diagnosis for such cardiac diseases, the analysis of cardiac function of left ventricle is performed using a CT or a MR image, whereby a region having abnormal cardiac motion may be detected. The present applicant proposes, for example, a method for fusion displaying a functional image representing cardiac function and an anatomical image representing a coronary artery in a predetermined format in U.S. Patent Application Publication No. 20100074487. In the mean time, MR delayed contrast enhancement analysis for detecting an ischemia area (necrosis area) of myocardium has been drawing attention, and this may indicate which part of the myocardium has an infarction as described, for example, in a non-patent document “Studies of Three-dimensional Cardiac Late Gadolinium Enhancement MRI at 3.0 Tesla”, by Ishimoto Takeshi, et al, Journal of Radiological Technology, Japanese Society of Radiological Technology, Vol. 64, No. 12, pp. 1554-1561, Dec. 2008.